The microcomputer industry is continually increasing the size, capabilities, and performance of its microcomputers (desk top, portables, lap top, etc.). Technology, however, is quickly reaching practical, if not theoretical, limits in the size and performance of printed circuit boards (PCBs).
The capabilities of Central Processing Units (CPUs) continue to increase in functionality and performance. The families of CPUs offered by Intel, for example, have steadily increased from 8 to 16 to 32 bits and from 4 MHz to 20 MHz or higher. The heavy competition between microprocessor manufacturers in the marketplace causes a continual increase in system capabilities, functionality and performance--while at the same time reducing the cost to the consumer. Unfortunately, even as CPU performance and speeds increase, PCBs are constrained to remain the same size or even decrease in size.
Although PCB design, technology, and capabilities have improved over the years, PCBs are designed and fabricated today based on fundamentally the same technical concepts as when they were first introduced. They still rely on etching the metallic circuit or system interconnect pathways upon some form of substrate and soldering the components (e.g, integrated circuits (ICs) and the like) to the metallic pathways. PCB component packing densities are being pushed to their limits. Unfortunately, as packing densities increase, both part counts and CPU sizes increase. In addition, system speeds and throughputs are constrained (and are now reaching their practical limits). Current PCB based systems are also very susceptible to disruption due to electromagnetic interference (EMI), radio-frequency interference (RFI), electromagnetic pulse phenomena (EMP), etc.
Current technology offers limited immediate solutions in the form of PCB layouts, board geometries, and integrated circuits that significantly improve system speed. Unfortunately, current technical capabilities, designs, and applications using various methods of photo and light transmission, IC socket design, and new board technologies are not being developed to their fullest potentials.
An effort to bridge this gap is demonstrated in U.S. Pat. No. 4,695,120 issued to J. D. Holder and U.S. Pat. No. 4,732,446 issued to L. Gipson et al. Both of these disclosures relate to attempts to incorporate fiber optics within the framework of the integrated circuit. This is, however, a very cumbersome method both in an electrical as well as a mechanical sense. An article in Computer Design, Oct. 15, 1988, "Hybrid Board Scheme Bridges Optical and Electrical Circuitry", pp. 38-41, very accurately points out that the state-of-the-art in miniature and micro fiber optics has a long way to go to produce an effective product.